Oracle使用须要注意的一些技巧

使用or时，Oracle会将or左右的语句视为两个分别查询，以下方语句

select * from T_JC_tools where jc_id='11024418' and eff_Station is null or eff_station='北京' and  jc_id='11024418' and delete_time is null;

实际中会将前面和后面总体分割开

select * from T_JC_tools where （jc_id='11024418' and eff_Station is null ）or （eff_station='北京' and  jc_id='11024418' and delete_time is null）;

因此咱们须要在or查询的条件先后加上（）保证查询的准确性

select * from T_JC_tools where jc_id='11024418' and (eff_Station is null or eff_station='北京') and  jc_id='11024418' and delete_time is null;